public class J2zhoukao {
    public static void main(String[] args) {
        for (int i = 0; i < 4; i++) {
            for (int j = 3; j > i; j--) {
                System.out.print(" ");
            }
            for (int j = 0; j < 2*i+2; j++) {
                System.out.print("@");
            }
            System.out.println();
        }
    }
}
